FIG. 1 is a block diagram of a conventional flash memory device. As shown in FIG. 1, the flash memory device 1 includes a flash cell array 6, a protective circuit 4, a first peripheral circuit 2, and a second peripheral circuit 8. The flash cell array 6 is a data storage device that includes a plurality of flash memory cells. These flash cells may comprise, for example, static gate type flash cells, split gate type flash cells or any other type of flash memory cell. The protective circuit 4 may be used to control the use of the flash memory device when the flash cell array is connected to an external logic circuit. The protective circuit 4 may include an array of metal fuses that are set (i.e., cut or not cut) so as to control the use of the flash memory device in a desired fashion.
The first peripheral circuit 2 is used to change the address of a defective cell in the flash cell array 6 into the address of a redundancy cell. Such a capability is provided because one or more cells in the flash cell array may be defective. When a defective cell is detected, the first peripheral circuit 2 changes the address of the defective cell into the address of one of the redundancy cells in order to “replace” the defective cell with one of the redundancy cells. The first peripheral circuit 2, like the protective circuit 4, may include an array of metal fuses. The address of the redundancy cell is changed to the address of the defective cell by cutting one of the metal fuses of the first peripheral circuit 2 using, for example, a laser bean.
The second peripheral circuit 8 controls the DC level so that desired reference values may be provided irrespective of the manufacturing processing conditions used during the fabrication of the flash memory device (which may impact the DC levels provided). The second peripheral circuit 8 may also include an array of metal fuses. In order to provide reference values regardless of semiconductor manufacturing processes of the flash memory, the second peripheral circuit 8 minutely controls a connection of the metal fuse according to respective conditions, and provides a fixed reference value(s).